1. Field of Invention
This invention relates to the field of engine analyzing devices for spark plug ignited combustion engines.
2. Description of the Previous Art
The purpose here is to analyze an engine's operation by an analysis of the voltage produced by a spark plug.
In ordinary operation, the magnitude of a spark plug's voltage is determined by the spark plug itself and not by the ignition system. The spark plug determines the spark size by its gap size and by the material within the gap. The gap of a spark plug changes only slightly with the miles of operation of a motor vehicle engine. VoItage, however, changes rapidly from one burn cycle to the next. These changes are due possibly to the material changes within the gap of the spark plug from one burn cycle to the next.
As a cylinder in an engine burns its fuel, it produces ionized gases and the more gases there are in the spark plug gap from burning, the lower the electrical resistance across that gap will be. This lower resistance will reduce the magnitude of the voltages across the spark plug gap.
Current engine analysis devices may have the ability to display a particular characteristic of a spark voltage that is processed by the apparatus of this invention. Those devices may also function to determine an average value for that characteristic. However, no current engine analysis devices can process a voltage to produce an output that is an instantaneous running average of the characteristic. Further the device herein provides information about the burning process inside an engine that no other device is known to provide.
Reference is had to U.S. Pat. No. 5,387,870, to Knapp, which covers an analysis of spark waveform of the breakdown voltage, but does not see the entire waveform and this is critical. Knapp's disclosure only works in real time because he samples, whereas the invention reads the waveform continuously. The invention herein also differs in that Knapp does not utilize collapsing field voltage, whereas the invention herein utilizes the entire waveform, including the collapsing field voltage which indicates engine combustion performance.